How to fix SharePoint error: Cannot complete this action

While my team was working on customizing a SharePoint site, we encountered the following error message

Cannot complete this actionEvent message: An unhandled exception has occurred. Process information:
Process ID: 1964
Process name: w3wp.exe
Account name: NT AUTHORITY\NETWORK SERVICE
Exception information:
Exception type: SPException
Exception message: Cannot complete this action. Please try again.
Thread information:
Thread ID: 6
Thread account name: NT AUTHORITY\NETWORK SERVICE
Is impersonating: False
Stack trace: at
Microsoft.SharePoint.Library.SPRequest.GetListItemDataWithCallback(String bstrUrl,
String bstrListName, String bstrViewName, String bstrViewXml,
SAFEARRAYFLAGS fSafeArrayFlags, ISP2DSafeArrayWriter pSACallback,
ISPDataCallback pPagingCallback, ISPDataCallback pSchemaCallback) at Microsoft.SharePoint.SPListItemCollection.EnsureListItemsData() at Microsoft.SharePoint.SPListItemCollection.get_Count() at ProjectCreation.ProjectCreation1.CreateChildControls() at System.Web.UI.Control.EnsureChildControls() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.WebControls.WebParts.WebPart.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

This information was hardly of any use in fixing the issue. We discovered the precise information in the SharePoint log files in%Program Files%\Common Files\Microsoft Shared\web server extensions\12\LOGS.

Given below is the message logged when the error was encountered.
Failed to find tag corresponding to ID "112", tried both onet.xml for site definition ID "1" language "1033" and global site definition. Operation failed.

Further investigation revealed that in the process of customizing the site, the team had overwritten the global version of ONET.xml file(218 KB) witha version that was 17 KB in size and it did not have ListTemplate tag. Replacing it with the original file resolved the issue.